U.S. patent application number 13/328699 was filed with the patent office on 2012-08-23 for device for capturing and transferring a measured value, series connection, system for capturing and transferring measured values, and household appliance.
Invention is credited to Dieter Genschow, Olaf Krause.
Application Number | 20120212274 13/328699 |
Document ID | / |
Family ID | 43122962 |
Filed Date | 2012-08-23 |
United States Patent
Application |
20120212274 |
Kind Code |
A1 |
Genschow; Dieter ; et
al. |
August 23, 2012 |
DEVICE FOR CAPTURING AND TRANSFERRING A MEASURED VALUE, SERIES
CONNECTION, SYSTEM FOR CAPTURING AND TRANSFERRING MEASURED VALUES,
AND HOUSEHOLD APPLIANCE
Abstract
A device includes a logic circuit having first, second, and
third input ports, a first output port, and a feedback path between
the first output port and the third input port. In a first
operating state, a logic state change at the first input port
triggers a logic state change at the first output port, but a logic
state change at the third input port does not trigger a logic state
change at the first output port. This allows signals to be routed
through the device. In a second operating state, a logic state
change of the third input port triggers a logic state change of the
first output port. This change is fed back, delayed by a time
value, to the third input to maintain an oscillation with at least
two edges. The frequency of this oscillation is used to determine a
value of a measurement variable.
Inventors: |
Genschow; Dieter; (Berlin,
DE) ; Krause; Olaf; (Neuruppin, DE) |
Family ID: |
43122962 |
Appl. No.: |
13/328699 |
Filed: |
December 16, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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PCT/EP2010/058458 |
Jun 16, 2010 |
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13328699 |
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Current U.S.
Class: |
327/290 ;
327/261 |
Current CPC
Class: |
G08C 21/00 20130101;
G01D 21/00 20130101 |
Class at
Publication: |
327/290 ;
327/261 |
International
Class: |
H03H 11/26 20060101
H03H011/26 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 16, 2009 |
DE |
10 2009 025 396.3 |
Claims
1. A device for capturing and transferring a measured value, the
device comprising a logic circuit having a first input port, a
second input port, a third input port and a first output port, and
a feedback path which provides a connection between the first
output port and the third input port and which is configured to
feed back a change in the state of the first output port to the
third input port delayed by a time value, wherein the feedback path
comprises an impedance which is configured to change in response to
the measured value and consequently change the time value of the
feedback in the feedback path, and wherein the logic circuit is
configured to set a first or a second operating state depending on
whether a first or a second logic state is present at the second
input port, wherein in the first operating state a change of a
logic state at the first input port triggers a change of a logic
state of the first output port and a change of a logic state at the
third input port does not trigger a change of the logic state at
the first output port, and in the second operating state a change
in the logic state of the third input port triggers a change of the
logic state of the first output port.
2. The device according to claim 1, the logic circuitry comprising:
a first digital element comprising the first input port, the first
output port and a fourth input port, wherein the first element is
configured to change the state of the first output port upon a
change in state in one of the first and fourth input ports, a
second digital element comprising the second and the third input
port and a second output port, wherein the second digital element
is configured to trigger a change in the logic state of the second
output port upon a change in the logic state of the third input
port, given that a first logic state is present at the second input
port, and is configured to maintain the logic state at the second
output port constant even if the logic state of the third input
port changes, given that a second logic state is present at the
second input port, wherein the second logic state is different from
the first logic state, wherein the second output port is logically
connected to the fourth input port such that a change in the logic
state of the second output port leads to a change in the logic
state of the third input port.
3. The device according to claim 2, wherein the first digital
element is configured as an XOR-element.
4. The device according to claim 2, wherein the second digital
element is configured as an AND-element, and wherein the third
input port is negated.
5. The device according to claim 1, wherein the impedance comprises
a resistive element which is arranged in series in the feedback
path and/or which comprises a capacitive element which is connected
to the feedback path and connected to ground.
6. The device according to claim 1, wherein a hysteresis element is
arranged before the third input port or at the third input port, or
the third input port is provided with hysteresis
characteristics.
7. The device according to claim 1, wherein the device comprises a
plurality of impedances, which can be selectively switched to the
feedback path via a selection element.
8. The device according to claim 1, wherein a drain element is
provided at the third input port, the drain element configured to
temporarily switch the feedback path against a high resistance or
against ground.
9. The device according to claim 1, wherein the second element with
the feedback path is configured as an oscillator, preferably as a
relaxation oscillator.
10. The device according to claim 1, wherein the impedance
comprises an electrode.
11. The device according to claim 1, wherein the feedback path is
connected to the second output port instead of the first output
port.
12. A series connection of at least a first and a second device
each according to claim 1, and wherein the output of the first
device is electrically connected to the input of the second
device.
13. The series connection according to claim 12, wherein at least
one of the first and second devices of the series connection
comprises a plurality of impedances which can be selectively
switched to the feedback path via a selection element.
14. A system for capturing and transferring of measured values, the
system comprising a series connection according to claim 12,
comprising a control device having at least a first and a second
activation output, the first activation output connected to the
second input port of the first device and the second activation
output connected to the second input port of the second device, and
comprising a receiving port which is connected to the first output
port of a last device in the series connection.
15. System according to claim 14, the control device being
configured to capture the number of edges at the receiving port per
unit of time and to thus capture the measured value that is being
signalized.
16. A household appliance comprising the series connection of claim
12, wherein the impedance is at least partially comprised in a
sensor element or a button, so that an approach or a touch of the
sensor element or an actuation of the button can be detected.
Description
CROSS REFERENCES TO RELATED APPLICATIONS
[0001] This application is a continuation of international patent
application PCT/EP2010/058458, filed on Jun. 16, 2010 designating
the U.S., which international patent application has been published
in German language and claims priority from German patent
application DE 10 2009 025 396.3, filed on Jun. 16, 2009. The
entire contents of these priority applications are incorporated
herein by reference.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to a device for capturing and
transferring a measured value, in particular a measured value which
indicates an approach or touch related to at least one sensor
element.
[0003] The present invention also relates to a series connection of
at least a first and a second device as mentioned before.
[0004] Even further, the present invention relates to a system for
capturing and transferring measured values, in particular measured
values which indicate an approach or a touch related to sensor
elements.
[0005] Still further, the present invention relates to a household
appliance comprising a device as mentioned before or a series
connection as mentioned before or a system as mentioned before.
[0006] Today's technical devices comprise a plurality of sensors,
detectors, switches, buttons, etc. Querying and evaluating these
elements becomes more difficult and more expensive as a number of
such elements increases and presents a notable expense factor, in
particular for household devices or for input devices in an
automobile.
[0007] One idea is to use a central control device to which all
sensors, detectors, switches, buttons, etc. are directly connected.
Such an arrangement can be provided rather easily. However, it has
the drawback that as the distance between the control device and an
individual element increases, longer cabling or wiring becomes
necessary. If a plurality of elements is at a distance from the
control device, the amount of the required wiring is
multiplied.
[0008] Another idea is to use a bus system, typically a bus system
with a ring architecture where all elements are connected to the
nearest coupling point into the bus system. This allows to
significantly reduce the total amount of wiring. However, the
drawback is that the implementation of a bus system is a
significant expense factor on its own. In addition, both ideas
require additional efforts in order to capture the measured values,
provide them to the control device and evaluate them at the control
device.
[0009] It is an object of the present invention to provide an
improved device for capturing and transferring a measured
value.
[0010] It is a further object of the present invention to provide
an improved series connection of devices as mentioned before.
[0011] Even further, it is an object of the present invention to
provide an improved system for capturing and transferring measured
values.
[0012] Still further, it is an object of the present invention to
provide an improved household appliance.
SUMMARY OF THE INVENTION
[0013] According to a first aspect of the present invention there
is provided a device comprising [0014] a logic circuit having a
first input port, a second input port, a third input port and a
first output port, and [0015] a feedback path which provides a
connection between the first output port and the third input port
and which is configured to feed back a change in the state of the
first output port to the third input port delayed by a time
value,
[0016] wherein the feedback path comprises an impedance which is
configured to change in response to the measured value and
consequently change the time value of the feedback in the feedback
path, and
[0017] wherein the logic circuit is configured to set a first or a
second operating state depending on whether a first or a second
logic state is present at the second input port, wherein [0018] in
the first operating state a change of a logic state at the first
input port triggers a change of a logic state of the first output
port and a change of a logic state at the third input port does not
trigger a change of the logic state at the first output port, and
[0019] in the second operating state a change in the logic state of
the third input port triggers a change of the logic state of the
first output port.
[0020] Such device allows to obtain a number of advantages with
only some of them being explained in the following.
[0021] One way to view the functionality is that an information
signal at the input of the device can be routed to the output of
the device if the second input port is in a constant state, in
particular when the second element has been switched passive. On
the other hand, if the second element is active and the state at
the first input port is constant, the signal from the feedback path
can be routed to the first output.
[0022] Since the device offers the functionality to route a signal
from its input to its output as well as providing a signal to the
output which has been generated within the device, it does not
require notable efforts to arrange multiple devices in series, with
practically no limit to the number of devices.
[0023] In the context of capturing a logic state it is advantageous
to use thresholds. When considering a scale from 0% to 100% of all
levels/values which can be present at an input port, wherein 0%
represents the minimum value and 100% represents the maximum value,
it is advantageous if the threshold for one of the logic states, in
particular "1", is above 50%, preferably above 70% and even more
preferably above 90%. Alternatively or in addition the threshold
for the other logic state, in particular "0", is below 50%,
preferably below 30% and even more preferably below 10%. This
allows to stabilize the performance of the feedback path. In
particular, the time value, which may also be referred to as a time
constant, of the feedback path can be increased, so that the
changes in state of the second output port occur more slowly and
can thus be detected more easily.
[0024] In this context it is pointed out that the differentiation
between "first" and "second" state is applied in order to
distinguish between two different states. The skilled artisan will
appreciate that the choice of whether the first state is "0" and
the second state is "1" or whether the first state is "1" and the
second state is "0" will depend on the specific implementation.
Such states relate to a particular element. This means that a first
state of one element does not necessarily have to match a first
state of another element.
[0025] The present invention even allows to process logic states
with a plurality of bits, e.g. two bits having the states "00",
"01", "10" and "11" or three bits having the states "000", "001",
"010", "011", "100", "101", "110" and "111". Still, using logic
states "0" and "1" allows for a simple and reliable design of the
device, since the logic states can be easily distinguished from one
another. Depending on the choice of terminology, the states can
also be described as "high" or "low". These logic states are
digital values which are represented by analog voltages. It may be
preferred that only states "0" and "1" can be present at the output
port, since this allows for an easy distinction of these
states.
[0026] In some embodiments it may be preferred that the logic state
"1" is represented by a voltage greater than 2.5 V, preferably
greater than 5 V and even more preferably greater than 10 V and
that the logic state "0" is represented by a value which is less
than 50% of the value for logic state "1", preferably less than 25%
and even more preferably less than 10%. Further, it may be
preferred that the logic state "0" is represented by a voltage of
approximately 0 V.
[0027] The impedance in the feedback path can be provided in a
number of different ways. It may comprise resistive and/or
capacitive and/or inductive characteristics, may be arranged in
series in the feedback path or may be connected to the feedback
path against another voltage potential, preferably against ground.
Other combinations of elements and connecting arrangements are
possible as well.
[0028] The impedance has the functionality in that it assumes
difference impedance values for different values of the measured
value and thus provides different time values or time constants in
the feedback path. This allows to relate the time value or time
constant to the measured value that is to be captured.
[0029] The functionality of the feedback path is now described in
more general terms, a more detailed description provided in the
context of the preferred embodiments. A change in state of the
second output port is provided to the third input port delayed by a
time value. When the change in state occurs at the third input
port, such results again in a change in state of the second output
port. This change in state, again, is provided to the third input
port delayed by a time value. If the second element is active the
changes in state of the second output port and of the third input
port are such that a change in state of the third input port
triggers such a change in state of the second output port that this
triggers again--delayed by a time value--a change in state of the
third input port, and so on.
[0030] In order to capture the measured value from the frequency
which will occur at the second output port, and then at the first
output port and at the output of the device, the following
approaches may be chosen in preferred embodiments. On the one hand
it is possible to specify a mathematical relation between the
measured value and the frequency due to the laws of physics. Then,
once a certain frequency is captured, the corresponding value of
the measurement variable can be captured. On the other hand, based
on practical experiments it can be captured which frequencies
represent which corresponding measured values. The corresponding
relationships are preferably stored in a look-up table and can then
be easily queried.
[0031] The time value or time constant for the feedback of the
feedback path is preferably between 10 ns and 100 ms, more
preferably between 1 .mu.s and 10 ms and even more preferably
between 10 .mu.s and 1 ms.
[0032] The provided device may preferably be used in the following
applications:
[0033] Proximity sensor, capacitive principle
[0034] Resistance strain gauge, resistive principle
[0035] Moisture sensor, capacitive principle
[0036] Light detector, differential-resistive principle
[0037] Temperature sensor, differential-resistive principle
[0038] Coil, inductive principle
[0039] Switch or button, resistive principle (ON/OFF)
[0040] One advantage of the device according to the present
invention lies in the trans-formation of a measured value into a
frequency. The following example may serve to illustrate this
advantage. A light sensor which is to provide measured values at
night as well as in bright sunshine, provides measured values in
the range of 0.01 lux and 100,000 lux. In order to represent this
signal, in particular using a voltage, without distortion and
without losses at a good resolution, e.g. 0.01 lux, a very
sophisticated measurement circuitry is required. If the signal is
to be digitized in a further step, this leads to additional
circuitry. When transforming the signal into a frequency, the
desired resolution can be obtained with reduced efforts. Since a
common microcontroller can capture a frequency with a good
accuracy, e.g. with a resolution of 0.001 Hz, a frequency range of
0.01 Hz to 100 kHz can be easily processed.
[0041] The wording used in the context of explaining the present
invention that a change in a logic state of an input port triggers
a change in a logic state of an output port, indicates that over
time a series of edges, two or more, at the input port is presented
over time as a series of edges, two or more, at the output port. It
is not required that the signals are identical. Rather, in
preferred embodiments, the signals may be inverted or delayed in
time. Rather, it is required that the series of edges over time at
the output port allows to make a determination regarding the
measured value. In other words, as long as a certain frequency for
the series of edges can be related to a measured value, the feature
is fulfilled that a change in a logic state of an input port
triggers a change in a logic state of an output port.
[0042] According to a refinement of the present invention the logic
circuitry comprises: [0043] a first digital element comprising the
first input port, the first output port and a fourth input port,
wherein the first element is configured to change the state of the
first output port upon a change in state of the first or the fourth
input port, [0044] a second digital element comprising the second
and the third input port and a second output port, wherein the
second digital element is configured to trigger a change in the
logic state of the second output port upon a change in the logic
state of the third input port, given that a first logic state is
present at the second input port, and is configured to maintain the
logic state at the second output port constant even if the logic
state of the third input port changes, given that a second logic
state is present at the second input port, wherein the second logic
state is different from the first logic state,
[0045] wherein the second output port is logically connected to the
fourth input port such that a change in the logic state of the
second output port leads to a change in the logic state of the
third input port.
[0046] The functionality of the first element is to change the
state at the first output port if the state of either the first or
the fourth input port changes. This means that the state of the
first output port changes only when either the state at the first
input port or the state at the fourth input port changes. However,
there is no change, if both states change at the same time.
[0047] Such a first element may offer the benefit that it is
transparent to changes of the first input port when the state of
the fourth input port is constant and that it is transparent to
changes of the fourth input port when the state of the fourth input
port is constant. The wording "transparent" is understood in the
sense that a change in the logic state of the corresponding input
port leads to a change in the logic state of the output port of the
element.
[0048] More specifically this may mean that a first information
signal at the first input port triggers a corresponding information
signal at the first output port when the state of the fourth input
port is constant. If a second information signal is present at the
fourth input port, a corresponding information signal is generated
at the first output port when the state of the first input port is
constant. Therefore, a first or a second information signal can be
switched transparently to the first output port.
[0049] It is pointed out that the information signal at the output
does not have to be identical to the information signal at the
input. For example, the invention may be practiced when the
amplitude of information signal at the output differs from the
amplitude of the information signal at the input. Also, the
information signal at the output may be inverted or delayed in
time. In order to practice the invention it is sufficient that the
information signal at the output comprises the same temporal
sequence of changes in the signal, in particular edges, as the
information signal at the input.
[0050] The device comprises the first digital element. The wording
"digital element" is to convey in the context of the present
invention as such elements that have discrete values at their
output port, but not arbitrary values. Such elements further have
the characteristic that changes in state at the input ports of such
element result in changes at the output port only in discrete
steps, but not on any for any infinitesimal small change. Such
digital elements may comprise, without being limited to, logic
elements, microprocessors and memory chips.
[0051] Since the device uses digital elements, sources of noise can
be more easily filtered than it is the case for analog signals.
[0052] The functionality of the second digital element is, in
connection with the feedback path, to trigger a signal at the
second output port that changes in response to the impedance of the
feedback path, in particular in view of the frequency. Further, the
second element can be set active or inactive via the second input
port. It is advantageous, when arbitrary changes at the third input
port do not trigger a change in state at the second output port,
unless a first logic state is present at the second input port.
Whether this state is chosen as "0" or "1" depends on the
particular implementation of the logic.
[0053] The capability to set the second element either to active or
passive, allows a particular functionality in connection with the
first element. If the second element is set passive, the fourth
input port of the first element remains in a constant state. This
allows to feed an information signal to the first input port of the
first element and to provide a corresponding information signal at
the first output port without any interference by a signal at the
third input port. If the second element is active, an information
signal is generated at the second output port, which is then
provided to the fourth input port of the first element. Thus, this
information signal is provided to the first output port
correspondingly if the first input port is in a constant state.
[0054] When the second element is active, a continually changing
signal is present at the second output port which is routed to the
output of the device via the first element. Based on the frequency
that underlie the changes in this signal, the value of the measured
variable can be obtained in a straight-forward manner.
[0055] According to a further refinement of the present invention
the first digital element is configured as an XOR-element.
[0056] This refinement is cost-efficient and reliable.
[0057] According to a further refinement of the present invention
the second digital element is configured as an AND-element, wherein
the third input port is negated.
[0058] This refinement is cost-efficient and reliable as well.
This, in particular, in combination with the previously referred to
XOR-element.
[0059] According to a further refinement of the present invention
the impedance comprises a resistive element which is arranged in
series in the feedback path and/or which comprises a capacitive
element which is connected to the feedback path and connected to
ground.
[0060] In general it is sufficient that only one element, either a
resistive element or a capacitive element, is connected in or to
the feedback path. Since the feedback path will always have a
certain resistance and a certain capacity, it may be sufficient to
have one element in the feedback path which changes the impedance
in the feedback path in relation to the measured value. If the
feedback path already comprises a resistive or capacitive element
which is dependent on the measured value, it may not be necessary
to provide a further element.
[0061] If, e.g., a conductor is used in the feedback path which
resistance and/or capacity changes dependent on the measured value,
no additional discrete element has to be provided, since the
feedback path already has a time value or a time constant which
depends on the measured value. It is pointed out that the impedance
may also comprise inductive components or may even consist of an
inductance only. Therefore, the impedance may be implemented by any
element or component which resistive and/or capacitive and/or
inductive portions depend on the measured value.
[0062] According to a further refinement of the present invention,
a hysteresis element is arranged before the third input port or at
the third input port, or the third input port is provided with
hysteresis characteristics.
[0063] This refinement allows to easily set the range of the
variability of the time value in the feedback path. This will mean,
in general, that the time value of the feedback path will increase,
the greater the distance is between the upper and the lower
switching point of the hysteresis. The hysteresis element is
preferably implemented as a Schmitt trigger. It may be particularly
advantageous, if the third input port of the second element
comprises such Schmitt trigger or if the third input port has the
characteristics of a Schmitt trigger.
[0064] According to a further refinement of the present invention
the device comprises a plurality of impedances, i.e. two or more
impedances, which can be selectively switched to the feedback path
via a selection element.
[0065] This refinement may offer the advantage that a device can
capture a plurality of measured values. Each impedance correlates
to a particular measurement variable. Then, if the measured value
of a particular measurement variable is to be captured, the
corresponding impedance is switched to the feedback path via the
selection element. The measured value is then captured according to
the procedure explained above. If another measurement variable is
to be captured, the other corresponding impedance is switched to
the feedback path, and the measurement value of the other
measurement variable is captured. In the context of this
application the term "switched to" comprises the meanings of
"switched to" and "switched into".
[0066] A preferred application may be that a plurality of control
areas of a control panel are each assigned an impedance. If it is
to be captured whether a finger is approaching one of the control
areas or whether one of the control areas has been touched or
pushed, this can be easily achieved. The individual impedances are
individually switched to the feedback path and the corresponding
measured values are evaluated. The selection element is preferably
configured as a multiplexer.
[0067] According to a further refinement of the present invention a
drain element is provided at the third input port, the drain
element configured to temporarily switch the feedback path against
a high resistance or against ground.
[0068] This allows a simplified implementation of the device which
will further be explained in the context of the preferred
embodiments.
[0069] According to a further preferred embodiment of the
invention, the second element with the feedback path is configured
as an oscillator, preferably as a relaxation oscillator.
[0070] This refinement allows to easily achieve the assignment
between the measured value to the captured and the resulting
frequency in the feedback path or of the second output port.
[0071] According to a further refinement of the present invention,
the impedance comprises an electrode.
[0072] This refinement allows for an easy implementation to measure
an approach towards a control element which comprises the
electrode. If a finger approaches the control element--and thus
approaches the electrode--, the capacity of the impedance changes,
and a certain time value or time constant is present in the
feedback path. Depending on the magnitude of the time value or
dependent on the captured frequency in the feedback path it can be
captured how close the finger is at the control element. Further,
it can be captured whether a touch has taken place, since this
results in a significant capacity change.
[0073] According to a second aspect of the present invention, a
series connection of at least a first and a second device is
provided, wherein the devices each correspond to the device as
described above, and wherein the output of the first device is
electrically connected to the input of the second device.
[0074] As already explained, the present device is well-suited for
a series connection. A series connection can be implemented easily,
since no further elements are required in order to achieve the
functionality of the series connection beyond those elements
already present in the individual devices. In a preferred
embodiment the driving of the devices is done in a coordinated
manner, which only activates the second element of one of the
devices in the series connection at a time. In particular, it is
preferred to connect at least three devices in the series
connection.
[0075] According to a further refinement of the present invention,
at least one of the devices of the series connection comprises a
plurality of impedances which can be selectively switched to the
feedback path via a selection element.
[0076] A corresponding preferred embodiment shows that it is
possible, in particular without special technical measures, to
connect one or more devices with one impedance in a mixed manner
with one or more devices with a plurality of impedances in
series.
[0077] According to a third aspect of the present invention a
system for capturing and transferring of measured values is
provided, in particular such measured values which indicate an
approach or a touch related to one or more sensor elements,
comprising a series connection as described above, and comprising a
control device having at least two activation outputs that are
individually connected to the respective second input ports of the
devices, and comprising a receiving port which is connected to the
first output port of the last device in the series connection.
[0078] The functionality of such a system will be explained in
detail in connection with a preferred embodiment. The system allows
to activate a desired second element in one of the devices via the
corresponding activation output. Due to the activation an
oscillation in the feedback path of the corresponding device takes
place which results in an information signal having a particular
frequency at the output of the corresponding device. Based on the
characteristics of the first element as described above, this
information signal is routed through all other devices, which are
passive, to the receiving port of the control device. Since the
control device has knowledge of which second element has been
activated, the control device can capture the measured value of the
desired measurement variable based on the frequency of the
information signal.
[0079] According to a further refinement of the present invention
the control device is configured to capture the number of changing
edges at the receiving port per unit of time and to thus capture
the measured value that is being signalized.
[0080] Based on the number of edges per unit of time the frequency
of the information at the receiving port can be captured. Since the
control device has knowledge what kind of impedance has generated
this frequency, the corresponding measured value can be calculated
or can be taken from a look-up table.
[0081] According to a fourth aspect of the present invention a
household appliance is provided, which comprises the device as
described above or a series connection as described above or a
system as described above, wherein the impedance is at least
partially comprised in a sensor element or a button, so that an
approach or a touch of the sensor element or an actuation of the
button can be detected.
[0082] The skilled artisan will appreciate that the previously
described features and the features to be described in the
following can be used in other combinations than those described
above and can be used as isolated features while still staying
within the scope and spirit of the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0083] Exemplary preferred embodiments of the present invention are
shown in the drawings and are further explained in the following.
In the drawings:
[0084] FIG. 1 shows a first embodiment of a device;
[0085] FIG. 2 shows a second embodiment of a device;
[0086] FIG. 3 shows a first embodiment of a system with a series
connection according to a first embodiment;
[0087] FIG. 4a shows a second embodiment of a series connection at
a point in time at which both second elements are passive;
[0088] FIG. 4b shows the series connection according to FIG. 4a at
a point in time at which the second element of the first device is
set to active;
[0089] FIG. 4c shows the series connection according to FIG. 4a at
a point in time at which a first change at the third input port of
the first device has taken place;
[0090] FIG. 4d shows the series connection according to FIG. 4a at
a point in time at which a second change at the third input port of
the first device has taken place;
[0091] FIG. 4e shows the series connection according to FIG. 4a at
a point in time at which the second element of the first device is
set back to passive;
[0092] FIG. 5 shows a third embodiment of a device;
[0093] FIG. 6 shows a fourth embodiment of a device;
[0094] FIG. 7 shows a fifth embodiment of a device; and
[0095] FIG. 8 shows a sixth embodiment of a device.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0096] FIG. 1 shows a device 10 for capturing and transferring a
measured value, in particular a measured value which indicates an
approach or a touch related to at least one sensor element. The
device comprises an input 14, an activation input 15, an output 16
and a logic circuitry 17.
[0097] The device 10 has a first digital element 18 having a first
input port 20, a fourth input port 22 and a first output port 24.
The first element 18 is configured to change the state of the first
output port 24 upon a change in state at the first or at the fourth
input port 20, 22. As shown, the first element 18 is preferably
configured as an XOR-element. The transfer function of the first
element 18 is chosen as follows:
TABLE-US-00001 First input port 20 Fourth input port 22 First
output port 24 0 0 0 0 1 1 1 0 1 1 1 0
[0098] The first input port 20 is electrically connected to the
input 14, and the first output port 24 is electrically connected to
the output 16.
[0099] The device 10 further comprises a second digital element 30
having a second input port 32, a third input port 34 and a second
output port 36. The second element 30 is configured to route--if a
second logic state is present at the second input port 32--changes
in the logic state of the third input port 34 into changes of the
logic state of the second output port 36.
[0100] Further, the second element 30 is configured such that--if a
first logic state is present at the second input port 32--a change
in the logic state of the first input port 20 triggers a change in
the logic state at the first output port 24, and a change in the
logic state at the third input port 34 does not trigger a change in
the logic state of the first output port 24.
[0101] The second element 30 is preferably configured as an
AND-element, wherein the third input port 34 is negated. The second
element 30 as shown here has the following transfer function:
TABLE-US-00002 Second input port 32 Third input port 34 Second
output port 36 0 0 0 0 1 0 1 0 1 1 1 0
[0102] The first output port 24 is connected to output 16. If a
measured value is to be captured by the device 10, the signal at
input 14 or at the first input port 20 is maintained constant, so
that the first element 18 generates a signal at its first output
port 24, the signal corresponding to the signal at its fourth input
port 22. In other words, the first element 18 is transparent to the
signal that is provided at the second output port 36.
[0103] The device 10 further comprises a feedback path 40 which
provides a connection between the first output port 24 and the
third input port 34 and which is configured to feed back a change
in the state of the second output port 36 delayed by a time value v
to the third input port 34. As will be explained later on, the
connection may also be provided between the second output port 36
and the third input port 34 without passing through the first
element 18, see FIGS. 7 and 8.
[0104] The feedback path 40 comprises an impedance 12 which is
configured to change in response to the captured measured value and
to thus change the time value v of the feedback in the feedback
path 40.
[0105] In this embodiment the impedance 12 comprises a resistive
element 42 which is arranged in series in the feedback path 40, and
comprises a capacitive element 44 which is connected to the
feedback path 40 and is connected to ground GND. However, it is
pointed out that it is in general sufficient to implement the
impedance 12 using a single element as long as the value of the
impedance 12 changes when the measured value changes and thus
changes the time value v of the feedback in the feedback path
40.
[0106] As is indicated by the hysteresis symbol at the second
element 30, the third input port 34 is provided with a hysteresis
characteristics. This allows a good control of the characteristics
of the oscillating circuit comprising the impedance 12. In other
embodiments it may be preferred to provide a hysteresis element 46
before (or in) the third input port 34 (see FIG. 2).
[0107] The shown embodiment is designed such that the first output
port 24 and the second output port 36 can either be in logic state
"0" or in logic state "1".
[0108] The second element 30 in combination with the feedback path
40 is embodied as an oscillator, preferably as a relaxation
oscillator, as will be seen from the following description of the
functionality of the device 10.
[0109] If a logic "0" is present at the activation input 15, a
logic "0" is always output at the second output port 36--regardless
of the state at the third input port 34.
[0110] The logic "0" which is output at the second output port 36
is fed back to the third input port 34 via the feedback path 40.
This results in a stable state, since due to the logic "0" at the
second input port 32, a logic "0" is always output at the second
output port 36.
[0111] The constant logic "0" that is present at the second output
port 36 in the idle state is also present at the fourth input port
22 of the first element 18. Therefore, the first element 18 is
transparent for an information signal which is present at the first
input port 20 and which is routed to the first output port 24.
Specifically, an information signal which is present at the input
14 of the device 10 is output via the first element 18 at output
16. As already explained, it is not necessary that the information
signal at output 16 is identical to the information signal at input
14. In the context of the present invention it is sufficient that
the information signal at output 16 has the same chronological
sequence of changes in signal, preferably edges, as the information
signal at input 14.
[0112] If a logic "1" is applied to the activation input 15, a
logic "1" at the second output port 36 results due to the logic "0"
at the third input port 34. Since the logic state at the first
input port 20 is kept constant, the change at the second output
port 36 from "0" to "1" leads to a change at the first output port
24: If a logic "0" is present at the first input port 20, the
second input port 24 changes from "0" to "1"; if a logic "1" is
present at the first input port 20, the state of the first output
port 24 changes from "1" to "0".
[0113] At the same time, the logic "0" of the second output port 36
is fed back via the feedback path 40 to the third input port 34
delayed by a time value v. This means that the level at the third
input port 34 starts to go down from the logic "1" towards the
logic "0". If the voltage at the third input port 34 is understood
as a logic "0", the state of the second output port 36 changes from
"0" to "1".
[0114] The logic "1" at the second output port 36 is almost
immediately available at the fourth input port 22 and leads to a
further change in state, preferably to an edge, at the first output
port 24 and at the output 16. The logic "1" at the first output
port 24 is again fed back to the third input port 34 delayed by the
time value v. Specifically, the voltage at the third input port 34
is now heading in the direction of the logic "1". If the particular
threshold for "1" is exceeded, the second element 30 interprets
this in a sense of a logic "1", and a further change in state at
the second output port 36 from "1" to "0" takes place.
[0115] Dependent on the specific value of the impedance 12 and the
corresponding time value v a sequence of signal changes, preferably
edges, is generated at the output 16 which convey by their
frequency the measured value to be captured.
[0116] If the activation input 15 is set again to "0", a logic "0"
results at the second output port 32 as well as--potentially
delayed--at the third input port 34. Thus, the oscillation in the
feedback path 40 stops, and the fourth input port 22 of the first
element is in a constant state. This allows again to transmit an
information signal from input 14 to output 16.
[0117] FIG. 2 shows a second embodiment of a device 10. The
impedance 12 is implemented such that a first impedance portion 48
is connected to connectors 50, 52 and is arranged in series in the
feedback path 40. The first impedance portion 48 is preferably
configured like the resistive element 42. A second impedance
portion 54 is connected to connectors 56, 58 to the feedback path
40 as well as to the ground connector GND. The second impedance
portion 54 may be preferably configured like the capacitive element
44.
[0118] It can be seen that the impedance 12 can be changed or
adapted easily. The first impedance portion 48 as well as the
second impedance portion 54 can be omitted, wherein in particular
the first impedance portion 48 can be replaced by a flat conductor
which naturally provides resistive and capacitive
characteristics.
[0119] Further, this second embodiment shows, as has been explained
above, that a hysteresis element 46 can be arranged before the
third input port 34.
[0120] FIG. 3 shows a series connection comprising a first, a
second and a third device 10a, 10b, 10c in a system 62 for
capturing and transferring of measured values, in particular
measured values that indicate an approach or a touch related to
sensor elements.
[0121] The devices 10a, 10b, 10c are a part of a household
appliance 72. The impedances of devices 10a, 10b are each a part of
a sensor element 74 and are configured as electrodes. The impedance
12 of the device 10c is a part of a button 76.
[0122] The devices 10a, 10b, 10c are of comparable structure,
wherein each device 10a, 10b, 10c has a suitable impedance 12. In
another embodiment, the impedances 12 may be configured differently
and/or may capture different measurement variables. In another
embodiment, the devices 10a, 10b, 10c may have different
structures, wherein in particular one or more devices 10a, 10b, 10c
may be embodied according to a third embodiment (see FIG. 5).
[0123] The system 62 comprises a control device 64 which comprises
a first, a second and a third activation output 66a, 66b, 66c which
are respectively connected with the respective activation input 15
or with a respective second input port 32 of the corresponding
device 10a, 10b, 10c.
[0124] The control device 64 further comprises a transmission port
68 and a receiving port 70. The transmission port 68 is connected
with the input 14 of the first device 10a. The output 16 of the
first device 10a is connected to the input 14 of the second device
10b. The output 16 of the second device 10b is connected to the
input 14 of the third, i.e. the last, device 10c in the series
connection 60. The output 16 of the last device 10c is connected to
the receiving port 70 of the control device 64.
[0125] If all activation outputs 66a, 66b, 66c are inactive, thus
preferably outputting a logic "0", all second elements 30 of the
devices 10a, 10b, 10c are passive. This configuration may be used
to test the functionality. To achieve this, a test signal is sent
from transmission port 68. The signal passes through all devices
10a, 10b, 10c and reaches the receiving port 70. In case the signal
received by the receiving port 70 does not correspond to an
expected signal, a problem in the system 62, in particular in the
series connection 60, may be assumed.
[0126] In order to query the measured values at the individual
devices 10a, 10b, 10c, the transmission port 68 is set into a
constant state, preferably it is set to a logic "0". Then, the
control device 64 may activate the first activation output 66a,
preferably using a logic "1". Via the activation input 15 and the
second input port 32 the second element 30 of the first device 10a
is now active.
[0127] As explained before, an oscillation starts involving the
feedback path 40 of the first device 10a which is output to output
16. Since the second elements 30 of the other devices 10b, 10c are
set passive, the information of the signal from the first device
10a is routed through the other devices 10b, 10c and finally
reaches the receiving port 70. The control device 64 is configured
to capture the number of edges at the receiving port 70 per unit of
time and may preferably capture the signalized measured value.
[0128] When the measured value of the first device 10a is captured,
the first activation output 66a is turned off, preferably set to a
logic "0", so that the second element 30 of the first device 10a
becomes passive. At output 16 of the first device 10a a constant
state is present again. The control device 64 now activates the
second activation output 66b, in particular by setting it to a
logic "1", so that the process that was just described now occurs
in the second device 10b. In the same manner, the measured value
from the last device 10c may be captured.
[0129] Based on FIGS. 4a to 4e it is explained how a first device
10a works together with a second device 10b. In order to ease the
understanding only a few reference numerals are shown. However, the
reference numerals continue to apply as they have been introduced
in the previous figures.
[0130] FIG. 4a shows the idle state in which both second elements
30 are set passive. At all inputs and outputs constant states are
present. In this example the output 16 of the second device 10b
outputs a logic "0". The course over time of the state of the
second output 16 of the second device 10b is shown each time at the
right hand side of each of FIGS. 4a to 4e in a small coordinate
system, wherein the abscissa shows the time and the ordinate shows
the logic state.
[0131] At a point in time t1, see FIG. 4b, the activation input 15
of the first device 10a is activated and the second output port 36
of the first device 10a outputs a logic "1". The result is that the
state of the first output port 24 changes from "0" to "1". This
again makes the first output port 24 of the second device 10b
change from "0" to "1". This change is shown in the diagram. It is
to be noted that the state at the third input port 34 of the device
10a does not immediately change, but only after a delay by the time
value v.
[0132] The time value v depends on the value of impedance 12.
Further, it depends on the choice of the lower and upper
thresholds. The further the thresholds are apart based on which a
"0" or a "1" is detected, the greater becomes v when a constant
impedance is assumed.
[0133] FIG. 4c shows the situation that the state at the third
input port 34 is captured as a logic "1" at a point in time t2.
This makes the second output port 36 of the first device 10a change
from "1" to "0", makes the first output port 24 of the first device
10a change from "1" to "0", and makes the first output port of the
second device 10b change from "1" to "0". This is shown in the
diagram.
[0134] FIG. 4d shows that it takes some time before the logic "0"
at the second output port 36 of the first device 10a is visible at
the third input port 34 of the first device 10a. When this is the
case, the second output port 36 of the first device 10a changes its
state again from "0" to "1". This again has the result that the
first output port 24 of the first device 10a as well as the first
output port 24 of the second device 10b change their state. The
result is shown in the diagram.
[0135] Finally, FIG. 4e shows that the activation input 15 of the
first device 10a is again set to "0" and that the second element 30
of the first device 10a becomes passive. Therefore, again an idle
state is reached where all inputs 14 and outputs 16 have a constant
state.
[0136] FIG. 5 shows a third embodiment of a device 10. The device
10 comprises a plurality of impedances 12a, 12b, 12c which can be
selectively switched into the feedback path 40 via a selection
element 80. The choice of one of the impedances 12a, 12b, 12c is
done via a control line 82 which is connected to a selection port
84 of the selection element 80. If the first impedance 12a is to be
switched into the feedback path 40, this is signalized via control
line 82.
[0137] The selection element 80 which is preferably embodied as a
multiplexer connects the first impedance 12a with the third input
port 34 and ensures that the other impedances 12b, 12c are not
connected to the third input port 34. While there are preferred
embodiments where a plurality of impedances 12a, 12b, 12c is
connected to the third input port 34 at the same time, it seems
more preferable at this time to have only one impedance 12a, 12b,
12c connected to the third input port 34. In this manner, one
device 10 allows to capture a plurality of measured values, here
three measured values, one after the other.
[0138] FIG. 6 shows a fourth preferred embodiment of a device 10.
In this embodiment a drain element 90 is arranged at the third
input port 34 which is configured to connect the feedback path 40
temporarily against a high impedance or against ground (GND). This
embodiment allows a somewhat simplified structure in comparison to
the first embodiment according to FIG. 1. When using this
embodiment the feedback path 40 can be logically "disconnected"
from the third input port 34, which means that a signal in the
feedback path 40 does not affect the third input port 34, so that
changes in the feedback path 40 cannot trigger a change in the
second element 30. It would also be possible to make a physical
separation, preferably the drain element 90 being a relay.
[0139] The drain element 90 comprises a release input 92 which is
connected to the activation input 15. When the release input 92 is
activated, in particular using a logic "1" the drain element 90
connects the feedback path 40 with the third input port 34. If the
release input 92 is inactive, in particular when a logic "0" is
present, the feedback path 40 is separated from the third input
port 34, preferably by the drain element 90 assuming high-impedance
characteristics. The drain element 90 is preferably embodied as a
buffer with tri-state-functionality.
[0140] The feedback path 40 is connected to the first output port
24 of the first element 18. As explained above, a change of the
second output port 36 leads to a change at the first output port 24
if--this being the working assumption here at this point--a
constant state is present at the first input port 20. Therefore,
the feedback can be obtained essentially in the same manner as if
the feedback path 40 is connected to the second output port 36.
Since the drain element 90 separates the feedback path 40 from the
third input port 34 if a logic "0" is present at the activation
input 15, even a forwarded signal, which leads to changes in state
at the first output port 24 cannot trigger an oscillation in the
feedback path 40.
[0141] FIG. 7 shows that the feedback path 40 may alternatively
also be connected to the second output port 36. This is possible
because--if the first input port 20 is kept constant--a change in
the logic state of the first output port 24 is caused by a change
in state of the second output port 36. Therefore, the feedback may
also occur via the second output port 36. Since the sequence of
logic states changes the device 10 has been adapted such that an
AND-element with a negated output (NAND-element) is used.
[0142] FIG. 8 shows that the second element 30 may also be
configured as a NORelement. In comparison to the previous
embodiments the second input port 32 is set to "0" if an
oscillation in the device 10 is to occur. If no oscillation is
desired the second input port 32 is set to "1".
* * * * *